The invention relates to a method for correcting a pressure value detected in a fluid on the basis of a pressure of a surrounding medium, as well as to a pump system with a level sensor and to the use of a pressure sensor in a corresponding pump system.
Submersible pumps are usually equipped with a level sensor or a level switch which switches the pump on and off in dependence of the fluid level in the pump sump. With this pressure sensors may be used as level sensors which detect the fluid pressure. Since the fluid pressure changes in dependence on the height of the fluid level above the pressure sensor, by way of the fluid pressure one may determine the liquid level and accordingly switch the pump on and off. With this however it is a problem that changes of the atmospheric pressure likewise have an effect on the detection by the pressure sensor. Thus when determining the fluid level inaccuracies occur due to fluctuations in the pressure of the surroundings. In order to compensate these, in the past differential pressure sensors have been applied as pressure sensors which determine the pressure difference between a fluid pressure and the pressure of the surroundings and thus permit the exact height of the fluid level above the pressure sensor to be determined. The application of these sensors however demands a tube or a flexible tubing to be led out of the pump sump in order to also be able to impinge the pressure sensor with the pressure of the surroundings. This renders the construction and the assembly of such pumps quite complicated.